Abstract The long-term objectives for this research will be to develop a broader base of knowledge regarding how sleep debt impacts fishermens' health and injury/fatality risk, and to develop viable, evidence-based practices to reduce these risks. Objective of This Application. This study proposes to close the current gap in sleep studies research by developing and trialing the technology, data collection tools, methods and protocols that are necessary for advancing sleep studies research in commercial fisheries in the years to come. In addition, the data generated from the proposed research activities will be used to generate hypotheses that can be further tested in expanded commercial fisheries sleep deprivation research in future. Specific Aim #1: In order to develop data collection tools that will be essential for completing the various phases of our proposed research, as well as future sleep debt studies, we will conduct qualitative interviews with commercial fisheries workers in Alaska (Salmon), Oregon (Dungeness Crab), North Carolina (Shrimp) and Massachusetts (Inshore Lobster). These same fisheries will also be invited to participate in sea trials of wrist actigraphy to assess the reliability of these devices for documenting sleep profiles in commercial fisheries workers. This data will be vital for completing the activities described in Specific Aim #2. Specific Aim #2: Using data from qualitative interviews and actigraphy sea trials the research team will develop and pilot data collection instruments and protocols that will capture health assessment, cognitive functioning and sleep profile data from fisheries workers in all four study regions (AK, OR, NC and MA). These tools will be assessed for accuracy, while protocols will be developed to maximize subject recruitment success and participation rewards. These activities will lead to the successful completion of Specific Aim #3 activities.Specific Aim #3: Once tools, methods and protocols have been developed and tested, Regional Investigators will work with an occupational health nurse to collect health and cognitive assessment data, as well as data on sleep patterns and quality. This information will be analyzed and prepared for Aim #4 activities. Specific Aim #4: Data summaries and researcher experiences will be used to generate hypotheses and develop recommendations for conducting future commercial fishing sleep debt studies. Information will be shared with other occupational health and safety researchers and with the fishing populations in each of the study regions. Data, methods and protocols will also be used to prepare an R01 application that will focus on more expansive research on this topic, as well as developing or testing evidence-based practices to mitigate the harmful effects of sleep debt in commercial fisheries workers. Expected Outcomes Include: data collection tools, methods and protocols for measuring sleep patterns and associated health/injury effects in commercial fisheries workers; data that can be used to facilitate further studies on these topics and the development of sleep debt interventions.